Dmitri Korobov, I'll take a stab at it. Most lenders (banks and HML) will only lend to a business for fix and flip investing, so forming an LLC would be the first step. Drafting a fair operating agreement is the crux here. It will spell out how profits will be distributed, who is liable for what, and how expenses are paid, and anything else you haven't thought of. It will also dictate how you and your partner will squash problems - mediation, litigation, etc. A good RE attorney will be able to guide you through this process fairly quickly.
Have you talked to any of your flipper's previous partners and how they did deals? I would ask for references and really vet the guy. If you are going to do business with this person you should really get to know them.
As far as getting around the 3 month cash balance. You can go the hard money route, but be sure you've really crunched the numbers because it's a ticking clock once you are funded.